personally,i would fog the engine,i use the way i described-this will also clean the injectors,hard to believe huh ?
reason behind fogging is,the engine=powerhead,is inside a cowling,it heats up and cools down in there-condensation all over,same thing happens inside the engine...
if you're in cape may,swing on by,i'm just off the parkway...you can drop the boat off when you're done with it and have it back next time you're heading down to fish...